The present invention is directed to an air control system for controlling the inflation pressures of tires on a trailer.
It is known, as disclosed in U.S. Pat. No. 5,287,906, to provide an automatic central tire inflation system (ATIS) in which the air in rotating tires is controlled through an air connection between the trailer air supply and each of the tires. The present invention is directed to an improved automatic tire inflation system.
Furthermore, most trailers are provided with a lubrication compartment at the end of the axle for containing lubricant for the wheel bearings. Such systems may include an oil sight glass and an oil plug for filling and inspecting the lubricant level in the lubricant compartment. In using an air inflation system, the air line may extend through the lubrication compartment. However, an inadvertent failure in the air control system, which is exposed to the oil filler plug, will blow out the oil filler plug and the lubricant with the consequential damage of burning out the bearings. Therefore, another feature of the present invention is the provision of a relief system for relieving any air pressure released in the air lubrication compartment for preventing the oil plug from being blown out.